In Pokemon Fire Red and Leaf Green, you have the choice of three Pokemon to start with. They are Charmander, Bulbasaur, and Squirtle. Charmander is a fire type, and gains a flying type when it evolves to its final form. Bulbasaur is a grass and poison type, and Squirtle is a water type.

Squirtle and Bulbasaur are effective against the first gym leader, where Charmander does poorly. Bulbasaur is the best against the second gym leader, Squirtle won't do much damage, and Charmander will take a beating. Bulbasaur and Charmander will be strong against the third gym leader, and Squirtle will probably be creamed. Against the fourth gym leader, Charmander is best, Squirtle is worst, and Bulbasaur is kind of neutral.